JP6929999B2 - The method, system, and stylus performed by the sensor controller - Google Patents

Description

The present invention relates to a method by which a stylus detects a sensor controller, a stylus, and a sensor controller.

A position detection device is known in which an active stylus (hereinafter, simply referred to as "stylus"), which is a position indicator with a built-in power supply device, transmits a signal to a tablet by capacitive coupling with the tablet. There is. In this type of position detection device, one-way communication is currently performed in which a signal is transmitted from the stylus and received by the sensor controller of the tablet. Patent Document 1 discloses an example of such a position detecting device.

Patent Document 2 discloses another example of the position detecting device. The stylus according to this example includes an electrode for signal transmission and a battery, and digitally transmits the result of pen pressure detection. In addition, the tablet is composed of a display device and a transparent sensor, and the transparent sensor is configured to be able to detect both the indicated position and writing pressure by the stylus and the touch position by the finger.

Patent Document 3 describes a position detecting device that transmits a signal in both directions via a coupling capacitance generated between the stylus and a sensor controller connected to the sensor. Paragraph 0065 describes that the touch sensor device sends a signal to the stylus and the stylus sends a signal in response to that signal.

International Publication No. 2015/11159 Japanese Unexamined Patent Publication No. 2014-63249 U.S. Patent Publication No. 2013/01076760

In communication via the coupling capacitance between the stylus and the sensor, the distance between the pen tip and the sensor electrode is generally different, although it depends on various factors such as the size, shape, material, and transmission voltage of the stylus tip or the electrode of the sensor. Sufficient coupling capacitance cannot be formed for effective communication unless it is within a few millimeters or tens of millimeters. Therefore, unlike the relationship between a computer and an input device such as a mouse equipped with a wireless communication unit such as Bluetooth®, which can detect each other in a range of several meters or several tens of meters and continue to maintain the communication. They cannot detect each other until it is time for the user to move the stylus closer to the sensor.

As a method of communicating between the stylus having such characteristics and the sensor controller, a detection process as shown in FIG. 10 described later can be considered. In this detection process, the power consumption of the stylus until the sensor controller is detected is large. There is a problem that it becomes. The details will be described below.

FIG. 10 is a diagram illustrating a method of detecting a sensor controller in a two-way communication system according to the background technology of the present invention. As shown in Tx in the figure, the sensor controller intermittently transmits a beacon signal BS containing control information (command) that is not shared in advance by the stylus to the stylus that has entered the sensing range at a constant transmission cycle TP. Configured to send. On the other hand, the stylus intermittently performs a reception operation until it detects the sensor controller. Specifically, the receiving circuit is activated at intervals indicated by the predetermined time length WP (for example, at intervals such as several times per second), and the reception period of the predetermined time length RP (<WP) is continuously obtained in order to obtain normal information. The reception operation is executed. The stylus performs the reception operation intermittently because it reduces the reception operation while the stylus is not used in the detection range of the sensor, such as when the stylus is actually placed beside an electronic device, and consumes power. This is to reduce.

In such a system, in order to guarantee that the control information included in the beacon signal BS is detected during the reception period of the predetermined time length RP after the stylus starts the reception operation, the predetermined time length RP is used. Must be longer than the transmission cycle TP (RP> TP must be). This is because when the predetermined time length RP is shorter than the transmission cycle TP, the predetermined time length RP elapses without detecting the beacon signal BS transmitted from the sensor controller depending on the timing when the stylus starts the reception operation, and the reception process ends. This is because it may end up. Therefore, it is desirable that the stylus 100 keeps activating the reception circuit during the continuous reception time RP, which is a period longer than the transmission cycle TP. In this case, the ratio of the stylus reception operation execution time to the total time is RP / WP. It becomes.

Originally, the stylus tends to have a smaller power supply capacity than the sensor controller that can share the power supply to drive the computer due to the limitation of the housing size, and when the power consumption of the stylus increases, the user's system It will reduce the usage time. In particular, in a stylus that performs reception operations synchronized with the transmitting side, it is necessary to drive at a higher speed than the transmission rate of the signal on the transmitting side in performing digital demodulation processing such as AD conversion and waveform reproduction. , The increase in the time length RP of the reception period becomes so large that it cannot be ignored. Therefore, it is required to reduce the power consumption of the stylus until the sensor controller is detected.

Here, if it is only necessary to reduce the power consumption of the stylus, it can be realized by extending the activation interval of the receiving circuit by the stylus (that is, increasing the predetermined time length WP). However, in that case, the maximum value (maximum standby time) of the time (response time) required from the stylus approaching the sensor controller to the completion of mutual detection becomes long. When the stylus is close to the sensor controller, it is highly likely that the user has actually started the operation using the stylus (pen-down operation), and the display processing of the indicated position of the stylus and the start of graphic processing are started. It is desirable that the time until the stylus detects the sensor controller and transmits the corresponding signal is short in order to accelerate the process.

Therefore, while maintaining the response time for the stylus to detect the sensor controller, the stylus configured to detect the sensor controller by receiving a signal transmitted by the sensor controller consumes until it detects the sensor controller. There is a need for a method that can reduce the amount of electric power.

The method according to the present invention is a method in which the stylus detects the sensor controller in a system including a sensor controller and a stylus that transmit signals by utilizing capacitive coupling, and the sensor controller is known. The first transmission step of transmitting the first control signal including two or more repetitions of the repetition element and the stylus perform a reception operation over a reception period of a predetermined time length and are received within the reception period. A detection step of determining whether or not one of the repeating elements is included in the signal and detecting the sensor controller according to the result of the determination, and the sensor controller in advance between the stylus and the detection step. It includes a second transmission step of transmitting a second control signal containing a plurality of unshared bit values.

The stylus according to the present invention is a stylus that communicates with a sensor controller via a coupling capacitance, and the sensor controller transmits a signal to the stylus during a continuous transmission period, and N (N is A signal is received during a reception period that is longer than the length of one or more symbols) and shorter than the continuous transmission period, and a value in the received signal is previously exchanged with the sensor controller. It is determined whether or not one repeating element consisting of the value of the N symbol shared by the above is included, and if the repeating element is not included as a result of the determination, the reception of the reception period signal is received. A receiver that continues at regular intervals and issues a start signal when the repeat element is included as a result of the determination, and a receiver for transmitting a signal to the sensor controller triggered by the start signal. Includes a control unit that executes processing.

The sensor controller according to the present invention uses a connected sensor to transmit control information to the stylus via a capacitive coupling between the sensor and the stylus, and a signal transmitted from the stylus in response to the control information. The stylus is a sensor controller that receives the signal, and the stylus performs a reception operation for a predetermined period of time, and determines whether or not the signal received within the reception period includes a pattern of one symbol value. The sensor controller is detected according to the result of the determination, and a value is set in advance in the stylus and a transmission unit that generates and transmits a control signal based on the value of the supplied symbol for a specified transmission period. It includes a control unit that controls the transmission unit so as to repeatedly transmit N (N is an integer of 1 or more) shared symbols for a period longer than the predetermined period.

According to the present invention, the stylus detects the sensor controller by repeatedly transmitting the repeating element two or more times and detecting one of the repeated repeating elements. The time required to execute the operation can be shortened, and the ratio of the reception operation execution time of the stylus to the total time can be reduced. Therefore, according to the present invention, a stylus configured to detect a sensor controller by receiving a signal transmitted by the sensor controller while maintaining a response time until the stylus detects the sensor controller. The amount of power consumed before detection is reduced.

It is a figure which shows the structure of the system 1 by embodiment of this invention. It is a figure which shows the structure of the electronic device 3 shown in FIG. It is a block diagram which shows the functional block of the stylus 100 shown in FIG. It is a timing diagram for explaining the operation of the stylus 100 and the sensor controller 31 shown in FIG. 1 in time series. (A) is a flow chart showing the operation of the sensor controller 31 shown in FIG. 1, and (b) is a flow chart showing the operation of the stylus 100 shown in FIG. It is a timing diagram for explaining the operation of the stylus 100 and the sensor controller 31 by the 1st modification of the Embodiment of this invention in time series. (A) is a flow chart showing the operation of the sensor controller 31 according to the first modification of the embodiment of the present invention, and (b) is the stylus 100 according to the first modification of the embodiment of the present invention. It is a flow chart which shows the operation of. It is a timing diagram for explaining the operation of the stylus 100 and the sensor controller 31 by the 2nd modification of the Embodiment of this invention in time series. (A) is a flow chart showing the operation of the sensor controller 31 according to the second modification of the embodiment of the present invention, and (b) is the stylus 100 according to the second modification of the embodiment of the present invention. It is a flow chart which shows the operation of. It is a figure explaining the detection method of the sensor controller in the bidirectional communication system by the background technique of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a configuration of a system 1 according to the present embodiment. The system 1 includes a stylus 100 and a sensor controller 31 provided in the electronic device 3.

As shown in FIG. 1, the stylus 100 includes a core 20, an electrode 21, a pen pressure detection sensor 23, a circuit board 24, and a power supply 25. As the power source 25, for example, a cylindrical AAAA battery is used.

The core 20 is a rod-shaped member arranged so that its longitudinal direction coincides with the pen axis direction of the stylus 100. A conductive material is applied to the surface of the tip portion 20a of the core 20 to form the electrode 21. The rear end portion of the core 20 is brought into contact with the pen pressure detection sensor 23. The pen pressure detection sensor 23 is used to detect the pressure (pen pressure) applied to the tip portion 20a of the core 20.

Similar to the active stylus described in Patent Document 1, the stylus 100 has a function of associating a change in an electric field with a change in a signal and transmitting a downlink signal DS toward the electronic device 3 via a coupling capacitance. The electrode 21 serves as an antenna for realizing this transmission. Although the details will be described later, the downlink signal DS includes the position signal DS_pos and the data signal DS_res. The electrode 21 of the stylus 100 also serves as an antenna for receiving the control signal US transmitted from the sensor controller 31 via the coupling capacitance.

The electronic device 3 includes a sensor 30 that constitutes a touch surface, a sensor controller 31, and a host processor 32 that controls the functions of each part of the electronic device 3 including these.

The sensor controller 31 has a function of transmitting a control signal US to the stylus 100 through the sensor 30. Although details will be described later, the control signal US includes a first control signal US_c1 and a second control signal US_c2.

The present invention relates to a method in which the stylus 100 detects the sensor controller 31 in the system 1 having the above configuration. The details will be described later with reference to FIG. 4, but in order to reduce the power consumption of the stylus 100, the pre-detection period BD until the sensor controller is detected is the reception operation of the receiving unit 71 except for the shortened reception period SRP. Is stopped.

FIG. 2 is a diagram showing the configuration of the electronic device 3. The electronic device 3 includes a sensor 30, a sensor controller 31, and a host processor 32 that controls the operation of the entire electronic device 3. The sensor 30 has a configuration in which a plurality of linear electrodes 30X and a plurality of linear electrodes 30Y are arranged in a matrix, and these linear electrodes 30X and 30Y are capacitively coupled to the stylus 100. Further, the sensor controller 31 includes a transmission unit 60, a selection unit 40, a reception unit 50, a logic unit 70, and an MCU 80.

The transmission unit 60 transmits the control signal US (first control signal US_c1 and second control signal US_c2) shown in FIG. 1 based on the supplied data (values of symbols described later) for a designated transmission period. It is a circuit for. Specifically, it includes a first control signal supply unit 61, a switch 62, a modulation unit (direct diffusion unit) 63, a diffusion code holding unit 64, and a transmission guard unit 65.

The first control signal supply unit 61 holds the repeating element c1 which is an element of the value pattern, and according to the instruction of the control signal ctrl_t1 supplied from the logic unit 70, the continuous transmission period TCP (for example, for example) of FIG. It has a function of continuously and repeatedly outputting the repeating element c1 over M (M is an integer of 2 or more) times during 3 msec). It also has a function of outputting a predetermined delimiter element STP immediately after the end of the continuous transmission period TCP.

The repeating element c1 is a pattern of symbol values used by the stylus 100 to detect the presence of the sensor controller 31 and is known to the stylus 100 in advance (before the stylus 100 detects the sensor controller 31). It is composed of the values of N symbols (N is an integer of 1 or more). A symbol is a unit of information used for modulation in transmission processing, and is a unit of information obtained by demodulating one symbol in reception processing. In the present embodiment, it will be described as a unit of information represented by the polarity or phase of one diffusion code.

The length of one symbol corresponds to the signal time (transmission time or reception time) for a unit of this information. The length of the N symbols is the time of the signal containing the N information units. One symbol may represent a one-bit value or a multi-value. When expressing a multi-value, it may indicate a value of a predetermined number of bits (a value corresponding to the power of 2; for convenience, it is expressed as "D"), or in addition to the value of a predetermined number of bits "D". It may indicate one or more values that do not correspond to any of the values of a predetermined number of bits (not used for the binary stringation used by the MCU). In addition, this "one or more values" is two in this invention, and is described as "P" and "M" respectively for convenience. These "P" and "M" are used only for the repeating element c1 and the delimiter element.

The N symbols constituting the repeating element c1 may all show the same first value, or may include a plurality of symbols showing different values from each other. For example, when one symbol indicates a 1-bit value, the repeating element c1 is composed of N (N = 2) symbols indicating the same first value "11" (or "00"). Alternatively, the repeating element c1 may be composed of "10" (or N (N = 2) symbols including 01) including symbols indicating "1" and symbols indicating "0" which are different from each other. ..

Further, if the value indicated by one symbol is multi-valued and includes the above "P" and "M", it corresponds to these specific values, for example, "PM" (or "MP"). The repeating element c1 may be constructed by using a value that does not. By doing so, when the values of any two consecutive symbols are decoded, it means that "the values of the two decoded symbols are different" regardless of whether it is "MP" or "PM". , It can be determined that the currently received signal is the first control signal.

Note that N = 1 (for example, the repeating element c1 may be "1"), and in this case, the minimum time required for the stylus 100 to detect the repeating element c1 (reception unit in the pre-detection period BD). The time required to keep 71 running. Specifically, the length of two symbols included in the repeating element c1) is minimized, and the shortened reception period SRP shown in FIG. 4 is used. It can be short. Further, by setting N = 2, the length of two symbols included in c1 included in the repeating element c1 increases to the length of four symbols in the reception period, but it is arbitrarily continuous. By decoding the values of the two symbols, it can be determined that the control signal currently being received is the first control signal.

Further, the delimiter element STP is a symbol pattern for notifying the stylus 100 of the end of the continuous transmission period TCP, and is composed of a symbol pattern that does not appear during the repetition of the repetition element c1. As an example, as described above, one symbol indicates a 1-bit value, and N symbols (N = 2) indicating the same first value "11" (or "00"). When the repeating element c1 is configured by, the delimiter element STP is configured by including a symbol indicating a value different from the first value “1”, for example, the second value “0” (“01”, “10”, “ It is preferably any one of "00"). Further, as described above, when multiple values are indicated by one symbol and N symbols are configured so that "P" and "M" are alternately repeated in the repeating element c1. , It is preferable to configure the delimiter element STP, for example, "PP" or "MM", only by symbols showing the same value (for example, "P"). The number of symbols constituting the delimiter element STP may be equal to the number of symbols constituting the repeating element c1.

The switch 62 selects one of the first control signal supply unit 61 and the MCU 80 based on the control signal ctrl_t2 supplied from the logic unit 70, and sends the selected output to the modulation unit (direct diffusion unit) 63. It has a function to supply. When the switch 62 selects the first control signal supply unit 61, the repeat element c1 or the delimiter element STP is supplied to the modulation unit (direct diffusion unit) 63. On the other hand, when the switch 62 selects the MCU 80, the control information c2 is supplied to the modulation section (direct diffusion section) 63.

The control information c2 is a symbol pattern including a command indicating the instruction content to the stylus 100, and is generated by the MCU 80. The control information c2 corresponds to the beacon signal BS including the control information (command) described in the background technology, and is information including a plurality of symbols whose values are not shared in advance with the stylus 100. In that respect, it differs from the repeating element c1. From the viewpoint of simplifying the decoding of the control information c2 in the stylus 100, the value indicated by each of the plurality of symbols that are not shared in advance is a specific value (or a specific value represented by the above “P” and “M”. It is preferable that each of them is associated with a value of a predetermined number of bits represented by "D", instead of being a bit string). The control information c2 constitutes a command for instructing the operation on the stylus 100 by the value of the predetermined number of bits. The command includes, for example, the content of information to be transmitted by the stylus 100, the timing at which the stylus 100 should transmit a signal, the frequency at which the stylus transmits a signal, and the like.

The spreading code holding unit 64 has a function of generating a spreading code PN (a predetermined code string) based on the control signal ctrl_t3 supplied from the logic unit 70. The diffusion code PN generated by the diffusion code holding unit 64 is supplied to the modulation unit (direct diffusion unit) 63.

The modulation unit (direct diffusion unit) 63 is a diffusion code PN supplied from the diffusion code holding unit 64 according to the value of each symbol of the signal (repeating element c1, delimiter element STP, control information c2) supplied from the switch 62. This is a functional unit that generates and outputs the first control signal US_c1 and the second control signal US_c2 described above by changing the output pattern. Specifically, the polarity of the diffusion code PN (forward or reverse, one symbol is many) based on the respective values of one or more symbols constituting the series of repeating elements c1 repeatedly supplied in the continuous transmission period TCP. The first control signal US_c1 is generated by changing the cyclic shift amount when expressing a value), and the spread code is determined by the values of a plurality of symbols constituting each of the delimiter element STP and the control information c2 supplied thereafter. It is configured to generate the second control signal US_c2 by changing the polarity of the PN and the like. The number of chips constituting one diffusion code PN is arbitrary, but the frequency spectra of the first control signal and the second control signal transmitted according to the rate of the chips are diffused to improve the noise immunity of the control signals. can do.

In the modulation section (direct diffusion section) 63, Manchester coding may be further applied to each chip constituting the first control signal US_c1 and the second control signal US_c2.

The transmission guard unit 65 performs a transmission operation and reception between the transmission period of the first control signal US_c1 and the second control signal US_c2 and the reception period RDS described later, based on the control signal ctrl_t4 supplied from the logic unit 70. Insert a guard period, which is a period during which both transmission and reception are not performed to switch operations.

The selection unit 40 is a switch that switches between a transmission period for transmitting a signal from the sensor 30 and a reception period for receiving a signal by the sensor 30 based on the control of the logic unit 70. More specifically, the selection unit 40 includes switches 44x and 44y and conductor selection circuits 41x and 41y. Based on the control signal sTRx supplied from the logic unit 70, the switch 44x connects the output end of the transmission unit 60 to the input end of the conductor selection circuit 41x during the transmission period, and connects the output end of the conductor selection circuit 41x during the reception period. It operates so as to connect the output end to the input end of the receiving unit 50. Based on the control signal sTRy supplied from the logic unit 70, the switch 44y connects the output end of the transmission unit 60 to the input end of the conductor selection circuit 41y during the transmission period, and connects the output end of the conductor selection circuit 41y during the reception period. It operates so as to connect the output end to the input end of the receiving unit 50. The conductor selection circuit 41x operates to select one of the plurality of linear electrodes 30X based on the control signal selX supplied from the logic unit 70 and connect the selected one to the switch 44x. The conductor selection circuit 41y operates to select one of the plurality of linear electrodes 30Y based on the control signal selY supplied from the logic unit 70 and connect the selected one to the switch 44y.

The receiving unit 50 is a circuit for detecting or receiving the position signal DS_pos and the data signal DS_res transmitted by the stylus 100 based on the control signal ctrl_r of the logic unit 70. Specifically, it includes an amplifier circuit 51, a detection circuit 52, and an analog-to-digital (AD) converter 53.

The amplifier circuit 51 amplifies and outputs the position signal DS_pos and the data signal DS_res supplied from the selection unit 40. The detection circuit 52 is a circuit that generates a voltage corresponding to the level of the output signal of the amplifier circuit 51. The AD converter 53 is a circuit that generates a digital signal by sampling the voltage output from the detection circuit 49 at predetermined time intervals. The digital data output by the AD converter 53 is supplied to the MCU 80.

The MCU 80 is a microprocessor that has a ROM and RAM inside and operates based on a program for executing the method of the present invention. The logic unit 70 outputs each of the above-mentioned control signals based on the control of the MCU 80. The MCU 80 also plays a role of deriving coordinate data x, y and the like indicating the position of the stylus 100 based on the digital data supplied from the AD converter 53 and outputting them to the host processor 32.

In this way, the MCU 80 includes a signal in which N (N is an integer of 1 or more) symbols whose values are shared in the stylus in advance are repeated M times by using the logic unit 70 and the transmission unit 60. The first control signal US_c1 is controlled to be transmitted.

Further, as a signal indicating a command to the stylus, a second control signal US_c2 including a symbol whose value is not shared with the stylus in advance is controlled to be transmitted.

The sensor controller 31 and the stylus 100 each store in advance the correspondence between each of the plurality of commands and a value (or bit string) different for each command. After determining the command to be transmitted, the MCU 80 of the sensor controller 31 is configured to acquire a bit string corresponding to the determined command from this correspondence and output it as control information c2.

FIG. 3 is a block diagram showing a functional block of the stylus 100. As shown in the figure, the stylus 100 includes a switching unit SW, a receiving unit 71, a transmitting unit 75, and a control unit 90.

The switching unit SW is a switch that switches between reception R and transmission T based on the control signal SWC from the control unit 90. In the case of reception R, the electrode 21 is connected to the reception unit 71, and in the case of transmission T, the electrode 21 is connected to the transmission unit 75. During the initial state, that is, during the pre-detection period BD until the stylus 100 detects the first control signal US_c1, the switching unit SW is set to the receiving side R.

The receiving unit 71 is a circuit that receives a signal supplied from the switching unit SW (a signal arriving at the electrode 21) and decodes the value of the symbol included in the received signal during the reception period instructed by the control unit 90. Yes, it includes a waveform reproduction unit 71a and a correlation calculator 71b. In order to reduce power consumption, the receiving unit 71 has stopped its operation in the pre-detection period BD until the sensor controller 31 is detected, except for the shortened reception period SRP.

Explaining with reference to FIG. 4, the receiving unit 71 has a shortened reception period SRP that is shortened as compared with the reception period RP described in FIG. 10 for each predetermined cycle WPa (for example, 2.5 msec). The first control signal US_c1 (repeating element c1) is received only for a while, and the repeating element c1 transmitted by the sensor controller 31 is detected. This detection is performed by determining whether or not one repeating element c1 is included in the signal received within the shortened reception period SRP specified by the control unit 90.

The reception period shortened here is longer than the time length of one repeating element c1 (length of N symbols) in the time of the period WPa, and is longer than the time length of the first control signal US_c1 (to N). The period is shorter than the length of the number of symbols multiplied by M). As described above, the time required to detect one repeating element regardless of the timing of transmission by the sensor controller 31 is the number of symbols (N) of the number of symbols included in the repeating element c1. The time may be longer than the length.

The stylus 100 attempts to detect the sensor controller 31 thereby. After detecting the sensor controller 31, the receiving unit 71 continues the receiving operation and performs a process of receiving the second control signal US_c2. Specifically, first, the delimiter element STP located at the head of the second control signal US_c2 is received, and then the control information c2 is received.

The operation of each unit of the receiving unit 71 will be specifically described. The waveform reproduction unit 71a binarizes the level of the electric charge (voltage) induced in the electrode 21 with a clock CLK that is several times (for example, four times) the chip rate of the diffusion code PN, and is a binary sequence of positive and negative polarity values (for example, four times). It has a function to format and output to (corresponding to the chip string of PN code).

The correlation calculator 71b stores the binary strings of positive and negative polarity values output by the waveform reproduction unit 71a in the register sequence, and while sequentially shifting with the clock CLK described above, the values are shared in advance from the sensor controller 31 and are known. By performing a correlation operation with the spread code PN corresponding to the value of the existing symbol, the value of the symbol included in the received signal is decoded and output.

Specifically, as described above, when the repeating element c1 is composed of only one symbol (for example, when the symbol "1" is predetermined as the content of the repeating element c1), the correlation calculator 71b Detects the existence of the sensor controller 31 when this one symbol can be detected once. Further, when the repeating element c1 is composed of a plurality of symbols (for example, the content of the repeating element c1 is N = 2, and the symbol value pattern "MP" or "PM" is predetermined. ), The correlation calculator 71b detects that the sensor controller 31 exists when the plurality of symbols can be detected once. The correlation calculator 71b that has detected the sensor controller 31 executes various processes for transmitting a signal to the sensor controller, such as a process according to a command included in the second control signal US_c2, to the control unit 90. Issuance of a start signal EN for making the process of.

Further, when the repetition element c1 is detected, the correlation calculator 71b continues the decoding process of the received signal (between time t1 and time t2 in FIG. 4), and the reception signal includes the delimiter element STP. Judge whether or not it is possible. As a result, when the delimiter element STP is detected at time t2, the detection time t2 is output to the control unit 90.

Further, the correlation calculator 71b receives the second control signal US_c2 according to the scheduling from the control unit 90 and decodes the control information c2 (including a plurality of "0" or "1" or unknown bit values). Output to the control unit 90.

The control unit 90 is composed of a microprocessor (MCU), and is activated when the start signal EN is supplied from the reception unit 71 (that is, the reception unit 71 detects one repeating element c1), and the sensor is activated. Performs various processes for transmitting signals to the controller. Specifically, a transmission / reception schedule for various signals (control information c2, position signal DS_pos, and data signal DS_res) is generated based on the detection time t2 supplied from the receiving unit 71, and a control signal based on the generated transmission / reception schedule is generated. The process of generating the SWC and supplying it to the switching unit SW and the process of controlling the transmission method of the data signal DS_res based on the control information c2 supplied from the receiving unit 71 are performed.

Further, the correspondence relationship between each of the plurality of commands included in the control signal US_c2 and the value of the symbol different for each command is stored in advance, and the value of the symbol supplied from the receiving unit 71 (value of a plurality of bits). Operates based on.

The control of the transmission method of the data signal DS_res will be described in detail. When the content of the information to be transmitted (pen ID, pen pressure value, side switch pressed state, etc.) is specified by the control information c2, the control unit 90 transmits the information to the electronic device 3 according to the specification. Control the contents of. Specifically, transmission data Res including information to be transmitted is generated and supplied to the transmission unit 75. Further, when the transmission timing of the data signal DS_res (for example, the time slot used for transmitting the data signal DS_res) is specified by the control information c2, the transmission unit 75 is such that the data signal DS_res is transmitted at that transmission timing. Controls the timing of supplying transmission data Res to. Further, when the frequency used for transmitting the data signal DS_res is specified by the control information c2, the modulation unit 73 described later is controlled so as to generate a carrier signal of that frequency.

If the receiving unit 71 has not detected the repeating element c1, that is, if the receiving unit 71 has not received the supply of the next activation signal EN after receiving the supply of the previous activation signal EN and completing the above processing, the control unit 71 has not yet received the supply of the next activation signal EN. The 90 may put the execution of each of the above processes into a paused state (that is, operate the processes of the control unit 90 with low power consumption). As a result, the power consumption of the control unit 90 can also be reduced.

The transmission unit 75 is a circuit that transmits the position signal DS_pos and the data signal DS_res, and is composed of a modulation unit 73 and a booster circuit 74.

The modulation unit 73 is a circuit that generates a carrier signal (rectangular wave signal) having a predetermined frequency or a frequency according to the control from the control unit 90, and outputs the signal as it is or after modulating it based on the control of the control unit 90. be. When transmitting the position signal DS_pos, the modulation unit 73 outputs the carrier signal as it is without modulating it. On the other hand, when the data signal DS_res is transmitted, the carrier signal is modulated (OK, PSK, etc.) by the transmission data Res supplied from the control unit 90, and the resulting modulated signal is output.

The booster circuit 74 is a circuit that generates a position signal DS_pos and a data signal DS_res by boosting the output signal of the modulation unit 73 to a constant amplitude. The position signal DS_pos and the data signal DS_res generated by the booster circuit 74 are transmitted from the electrode 21 to the space via the switching unit SW.

FIG. 4 is a timing diagram for explaining the operations of the stylus 100 and the sensor controller 31 in chronological order. Further, FIG. 5A is a flow chart showing the operation of the sensor controller 31, and FIG. 5B is a flow chart showing the operation of the stylus 100. In FIG. 4, the time axis indicated by the upper Ts indicates the transmission Tx and the reception Rx of the stylus 100. The time axis indicated by the lower Tt indicates the transmission Tx and the reception Rx of the sensor controller 31. Hereinafter, the operations of the stylus 100 and the sensor controller 31 will be described in detail with reference to these figures.

<1. Operation in BD during the period before detection>
(1-1: Until time t0)
In FIG. 4, the period up to time t0 is a period during which the stylus 100 is outside the detection range of the sensor controller 31. In order to reduce power consumption, the stylus 100 intermittently operates the receiving unit 71 a plurality of times with a period WPa shorter than that of the continuous transmission period TCP (steps S20 and S21 in FIG. 5B). Specifically, in each cycle WPa, the receiving unit 71 is operated only during the shortened reception period SRP in order to detect one repeating element c1, and the receiving unit 71 is stopped at other times. .. The time length of the reception period SRP is larger than a value necessary and sufficient for receiving the repeating element c1 once (for example, the length 2N of two N symbols included in the repeating element c1), and is repeated. Element c1 is set to a time shorter than the length of the symbol contained in the signal repeated M times).

The sensor controller 31 is configured to repeat the transmission of the first control signal US_c1 and the second control signal US_c2 in the period WP (steps S10 to S13 in FIG. 5A). As described above, the first control signal US_c1 is a signal composed of the repetition of the repeating element c1, and the second control signal US_c2 is a signal composed of the delimiter element STP and the control information c2.

Specifically, the sensor controller 31 repeats the transmission of the signal obtained by diffusing the repeating element c1 by the spreading code PN over the continuous transmission period TCP, which is a time longer than the periodic WPa, at the start of the periodic WP. This iteration is performed at least twice or more. The number of repetitions M is a number obtained by dividing the continuous transmission period TCP by the length of N symbols included in the repetition element c1. For example, when the continuous transmission period TCP is 1 millisecond, the number N of symbols included in the repeating element is 2, and the length of one symbol is 20 μsec, the number of repetitions M is about 25 times.

Here, a preferable value of the number of repetitions (M) of the repetition element c1 will be described. In order for the stylus 100 to be able to receive one time while the sensor controller 31 is continuously transmitting the repeating element c1, the stylus 100 has a repeating element at least once during the time length TCP. It is necessary to perform the reception operation. Therefore, WPa ≦ TCP (Equation 1). Further, if the number of repetitions of the repeating element c1 during continuous transmission is M as described above and the time required for transmission of one repeating element c1 is t, TCP = Mt. Therefore, from Equation 1, M ≧ WPa / t (Equation 2).

Since the time required for one reception is SRP, the ratio of the reception operation execution time of the stylus 100 to the total time is SRP / WPa. Therefore, in order to reduce the power consumption of the stylus 100 as compared with the background technique shown in FIG. 10, this SRP / WPa must be smaller than the RP / WP. That is, SRP / WPa <RP / WP (Equation 3).

From Equations 2 and 3, M> (SRP / t) / (RP / WP). Therefore, in order to reduce the power consumption of the stylus 100 as compared with the background technique shown in FIG. 10, it can be said that it is preferable to set the number of repetitions M to a value larger than (SRP / t) / (RP / WP). Since the sensor controller 31 transmits the first control signal US_c1 in the periodic WP, the response time (maximum standby time) required from when the stylus 100 approaches the sensor controller 31 until the mutual detection is completed. ) Is the same value as in the example of FIG. Therefore, according to the present embodiment, by setting the number of repetitions M to a value larger than (SRP / t) / (RP / WP), the maximum standby time is maintained at a value equal to or less than the conventional value. The amount of electric power consumed until the stylus 100 configured to detect the sensor controller 31 by receiving the signal transmitted by the sensor controller 31 is reduced.

By the way, the sensor controller 31 that has repeatedly transmitted the repeating element c1 over the continuous transmission period TCP continuously transmits the second control signal US_c2. Specifically, first, a signal obtained by spreading the delimiter element STP by the spreading code PN is transmitted, and then a signal obtained by spreading the control information c2 by the spreading code PN is transmitted. As described above, the control information c2 is a symbol pattern including a command. The “D” shown in FIG. 4 represents a symbol indicating a numerical value (rather than the “P” or “M” described above).

The sensor controller 31 that has completed the transmission of the second control signal US_c2 provides a reception period RDS for receiving the signal from the stylus 100 (step S14 in FIG. 5A). When the stylus 100 receives the first control signal US_c1 transmitted as described above, the stylus 100 is configured to transmit the position signal DS_pos within this reception period RDS. The sensor controller 31 waits for the reception of the position signal DS_pos thus transmitted during the reception period RDS.

(1-2. Time t0 to t1)
When the stylus 100 moves to the detection range of the sensor 30 at time t0 (stylus down), the stylus 100 moves to the sensor controller at the timing of time t1 immediately after the reception period SRP located in the continuous transmission period TCP that arrives thereafter. The repeating element c1 transmitted by 31 will be detected (YES in step S22 of FIG. 5B).

<2. Operation after the stylus 100 detects the sensor controller 31>
(Times t1 to t3)
When the stylus 100 detects the repeating element c1, the stylus 100 generates the above-mentioned activation signal EN, and after that, continues the reception operation (decoding process of the received signal) beyond the reception period SRP (step 5 (b)). S23). Then, when the sensor controller 31 transmits the delimiter element STP while the stylus 100 is performing this reception operation, the delimiter element STP is detected by the stylus 100 at the subsequent time t2 (step S24 in FIG. 5B). YES). The stylus 100 refers to the time t2 when the delimiter element STP is detected in this way, and schedules the transmission / reception of the control information c2, the position signal DS_pos, and the data signal DS_res. Specifically, as shown in FIG. 4, first, the reception of the control information c2 is waited at the timing based on the time t2 (step S25 in FIG. 5B), and then when the control information c2 is received (FIG. 5 (b). ), The position signal DS_pos is transmitted while generating the data signal DS_res (transmission data Res) according to the received control information c2 (step S27 in FIG. 5B), and finally generated. The data signal DS_res is transmitted (step S28 in FIG. 5B).

As described above, the sensor controller 31 provides a reception period RDS after the transmission of the second control signal US_c2, and waits for the reception of the position signal DS_pos (step S14 in FIG. 5A). The sensor controller 31 that has received the position signal DS_pos (YES in step S15 of FIG. 5A) has a stylus 100 based on the reception status of the position signal DS_pos at each of the plurality of linear electrodes 30X and 30Y shown in FIG. (Coordinate data x, y) is calculated and output to the host processor 32 shown in FIG. 1, the reception period RDS is set again, and the reception of the data signal DS_res is waited for this time (FIG. 5 (a). ) Step S16). The sensor controller 31 that has received the data signal DS_res extracts the above-mentioned transmission data Res from the received data signal DS_res and outputs it to the host processor 32.

Even after receiving the position signal DS_pos and the data signal DS_res from the stylus 100 in this way, the sensor controller 31 repeats the first control signal US_c1 and the second control signal US_c2 in the same manner as before. As a result, the stylus 100 also repeats the above-described operation, and the sensor controller 31 receives the position signal DS_pos and the data signal DS_res from the stylus 100 each time, thereby calculating the position of the stylus 100 and transmitting the stylus 100. Acquire data Res.

As described above, according to the system 1 according to the present embodiment, the sensor controller 31 side repeatedly transmits the repeating element c1 twice or more, and therefore, depending on the conventional RP / WP value (see FIG. 10). , The ratio of the reception operation execution time of the stylus 100 to the total time can be made smaller than before. Therefore, the sensor controller 31 transmits while maintaining the maximum value (maximum standby time) of the time required from the stylus 100 approaching the sensor controller 31 to the completion of mutual detection at a value equal to or less than the conventional value. The amount of power consumed by the stylus 100 configured to detect the sensor controller 31 by receiving the signal is reduced.

In the present embodiment, the delimiter element STP is positioned at the beginning of the second control signal US_c2, but it may be positioned at the end of the first control signal US_c1. In any case, the operation of the system 1 according to the present embodiment is the same.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and the present invention can be implemented in various embodiments without departing from the gist thereof. Of course.

For example, in the above embodiment, the sensor controller 31 transmits the second control signal US_c2 including the control information c2 portion each time the first control signal US_c1 is transmitted. However, in the pre-detection period BD, it is possible to configure the transmission of the second control signal US_c2 to be stopped by the delimiter element STP and to send the control information c2 only after the stylus 100 is detected. In the previous period BD, only the first control signal US_c1 (repeating element c1) is transmitted, and the second control signal US_c2 (separating element STP and control information c2) is sent only after the stylus 100 is detected. It is also possible. Hereinafter, each of the former modification (first modification) and the latter modification (second modification) will be described in detail with reference to the drawings.

FIG. 6 is a timing diagram for explaining the operations of the stylus 100 and the sensor controller 31 according to the first modification of the present embodiment in chronological order. Further, FIG. 7A is a flow chart showing the operation of the sensor controller 31 according to the present modification, and FIG. 7B is a flow chart showing the operation of the stylus 100 according to the present modification.

As shown in FIG. 6, the sensor controller 31 according to this example does not transmit the control information c2 after the transmission of the delimiter element STP in the pre-detection period BD, while the reception period RDS provided after the transmission of the delimiter element STP. When the position signal DS_pos is detected, the control information c2 is transmitted after the reception period RDS has elapsed, and then the reception period RDS is provided again to wait for the reception of the data signal DS_res from the stylus 100.

On the processing flow of the sensor controller 31, as shown in FIG. 7A, step S13 is executed after step S15. Further, on the processing flow of the stylus 100, as shown in FIG. 7B, a step S27a for transmitting the position signal DS_pos is provided immediately after the step S24, and when the data signal DS_res is generated (in FIG. 7B). In step S27b), the position signal DS_pos is not transmitted.

As described above, also in this modification, the sensor controller 31 can transmit the second control signal US_c2 and receive the data signal DS_res. Therefore, even in this modification, the maximum value (maximum standby time) of the time required from the stylus 100 approaching the sensor controller 31 to the completion of mutual detection is maintained at a value equal to or less than the conventional value. , It becomes possible to reduce the power consumption of the stylus 100 until the sensor controller 31 is detected.

FIG. 8 is a timing diagram for explaining the operations of the stylus 100 and the sensor controller 31 according to the second modification of the present embodiment in chronological order. Further, FIG. 9A is a flow chart showing the operation of the sensor controller 31 according to the present modification, and FIG. 9B is a flow chart showing the operation of the stylus 100 according to the present modification.

As shown in FIG. 8, the sensor controller 31 according to this example transmits only the first control signal US_c1 (repeating element c1) in the pre-detection period BD, while the reception provided after the transmission of the first control signal US_c1. When the position signal DS_pos is detected in the period RDS, the second control signal US_c2 (separator element STP and control information c2) is transmitted. Then, after that, the reception period RDS is set again, and the reception of the data signal DS_res from the stylus 100 is waited for.

Here, as shown in FIG. 8, the stylus 100 according to the present modification is configured to transmit the position signal DS_pos immediately after detecting the repeating element c1 once. When the stylus 100 is configured in this way, assuming that the time length required for the sensor controller 31 to receive the position signal DS_pos is T1, the stylus 100 has the position signal DS_pos over the time length TCP + T1-SRP as shown in FIG. Need to keep sending. This is because the reception period provided by the sensor controller 31 for receiving the position signal DS_pos even when the stylus 100 receives the first of the plurality of repeating elements c1 repeatedly transmitted by the sensor controller 31. This is to allow the stylus 100 to continue transmitting the position signal DS_pos until the end of the RDS. Further, the sensor controller 31 needs to start the transmission of the delimiter element STP after waiting for the time length TCP-SRP after the end of the reception period RDS for receiving the position signal DS_pos. This means that even when the stylus 100 receives the last transmitted of the plurality of repeating elements c1 repeatedly transmitted by the sensor controller 31, the stylus 100 is transmitting the position signal DS_pos (that is, that is). This is to prevent the sensor controller 31 from transmitting the delimiter element STP while the stylus 100 cannot receive the signal from the sensor controller 31).

On the processing flow of the sensor controller 31, as shown in FIG. 9A, step S17 that waits for the time length TCP-SRP is provided after step S15, and steps S12 and S13 are executed after step S17. It will be. Further, on the processing flow of the stylus 100, as shown in FIG. 9B, the position signal DS_pos is transmitted immediately after step S22 (step S27c in FIG. 9B), and the time length is TCP + T1-. The transmission of the position signal DS_pos will be continued over the SRP.

As described above, also in this modification, the sensor controller 31 can transmit the second control signal US_c2 and receive the data signal DS_res. Therefore, even in this modification, the maximum value (maximum standby time) of the time required from the stylus 100 approaching the sensor controller 31 to the completion of mutual detection is maintained at a value equal to or less than the conventional value. , It becomes possible to reduce the power consumption of the stylus 100 until the sensor controller 31 is detected.

Further, the sensor controller 31 determines the number of repeating elements c1 constituting the first control signal US_c1 to be transmitted after detecting the stylus 100 (after receiving the position signal DS_pos from the stylus 100) before detecting the stylus 100. The number may be smaller than the number of repeating elements c1 constituting the first control signal US_c1 to be transmitted. In this way, the power consumption of the sensor controller 31 can be reduced by an amount corresponding to the number of reductions of the repeating element c1. In this case, the sensor controller 31 restores (increases) the number of repeating elements c1 constituting the first control signal US_c1 when the signal from the stylus 100 is not received for a predetermined period or a predetermined number of times. Is preferable. By doing so, it is possible to avoid the occurrence of a situation in which the first control signal US_c1 is not received indefinitely the next time the stylus 100 approaches the sensor 30.

The sensor controller 31 may stop transmitting the first control signal US_c1 after detecting the stylus 100 (after receiving the position signal DS_pos from the stylus 100). That is, after that, only the second control signal US_c1 may be transmitted. In this case, the sensor controller 31 needs to restart the transmission of the first control signal US_c1 so that the stylus 100 can be detected again when the signal from the stylus 100 is not received for a predetermined period or a predetermined number of times.

Further, the sensor controller 31 may transmit the first control signal US_c1 and transmit the second control signal US_c2 after the gap period of a predetermined time length has elapsed. In this way, the stylus 100 can receive the second control signal US_c2 with a margin.

Further, in the second control signal US_c2, in addition to an arbitrary value (or bit string) constituting the control information c2, a first error detection value (or bit string) derived based on the value (or bit string) is used. It may be included. For the derivation of the first error detection value (or bit string), for example, it is preferable to use a cyclic redundancy check. The first error detection value (or bit string) is derived only based on the control information c2, and the repeating element c1 and the delimiter element STP constituting the first control signal US_c1 are the first error detection value (or bit string). ) Is not involved in the derivation.

When the second control signal US_c2 is configured to include the first error detection value (or bit string), the stylus 100 receives a second error detection value (or bit string) based on the received second control signal US_c2. Is performed. Specifically, the control information c2 (likely information) extracted from the second control signal US_c2 is subjected to the same calculation as that used by the sensor controller 31 for deriving the first error detection value (or bit string). The second error detection value (or bit string) is derived by. Then, the first error detection value (or bit string) (likely information) included in the received second control signal US_c2 is compared with the derived second error detection value (or bit string), and if they match, It is determined that the control information c2 can be correctly received, and the process proceeds to the next process. If they do not match, the extracted control information c2 is discarded and the reception of the next second control signal US_c2 is awaited. As a result, the stylus 100 can receive only the correct control information c2 from the sensor controller 31.

Further, the sensor controller 31 transmits immediately before the variable length so that the total bit length of the first control signal US_c1 and the second control signal US_c2 becomes constant according to the length of the second control signal US_c2. The first control signal US_c1 may be generated. Specifically, the length of the first control signal US_c1 may be adjusted by increasing or decreasing the number of repetitions of the repeating element c1. By doing so, it becomes possible to keep the bit length of the signal transmitted by the sensor controller 31 at a constant value at all times.

As described above, according to the system 1, the stylus 100, the sensor controller 31 according to the present invention, and the method executed by these, the sensor controller 31 side repeatedly transmits the repeating element two or more times, and the repeated repeating element Since the stylus 100 detects the sensor controller 31 by detecting one of them, the time that the stylus 100 has to execute the reception operation can be shortened, and the reception operation execution time of the stylus 100 can be shortened. It is possible to reduce the ratio of the total time. Therefore, the stylus 100 configured to detect the sensor controller 31 by receiving the signal transmitted by the sensor controller 31 while maintaining the response time until the stylus 100 detects the sensor controller 31 controls the sensor controller 31. The amount of power consumed before detection is reduced.

In the stylus 100, the control unit 90 may determine whether or not the reception signal includes the repeating element c1 instead of the reception unit 71. Further, in determining whether or not the repeating element c1 is included, the received signal and the waveform stored in advance are not compared with the value of the decoded symbol and the value of the symbol shared in advance in the stylus 100. It may be performed as a comparison of signal levels of shapes.

In the sensor controller 31, the pattern of the symbol value of the delimiter element STP has been described as being supplied in the transmission unit 60, but the MCU 80 may supply the pattern. Further, the MCU 80 and the logic unit 70 may be executed in one processor.

The N symbols are read as N codes or detection bit patterns, and the length of N symbols is read as the signal time to transmit the values of the N symbols or the bit strings included in the detection bit pattern. You may.

Although the system has been described as a system that transmits signals via capacitive coupling, the stylus and sensor controller use a method that can detect each other only at a distance of up to several tens of millimeters due to the large attenuation of the signal level with respect to the distance. , The present invention can be applied.

1 System 3 Electronic equipment 20 Core 20a Tip 21 Electrode 23 Pen pressure detection sensor 24 Circuit board 25 Power supply 30 Sensor 30X, 30Y Linear electrode 31 Sensor controller 32 Host processor 40 Selection 41x, 41y Conductor selection circuit 44x, 44y, 62 Switch 49 Detection circuit 50 Receiver 51 Amplifier circuit 52 Detection circuit 53 Analog digital converter 60 Transmitter 61 Control signal supply 63 Modulator (direct diffuser)
64 Diffuse code holding unit 65 Transmission guard unit 70 Logic unit 71 Reception unit 71a Waveform reproduction unit 71b Correlation calculator 73 Modulator 74 Booster circuit 75 Transmission unit 90 Control unit 100 Stylus BS Beacon signal c1 Repeating element c2 Control information DS Downlink signal DS_pos position signal DS_res data signal EN start signal PN diffusion code RDS, SRP reception period STP delimiter SW switching unit TCP continuous transmission period US control signal US_c1 first control signal US_c2 second control signal WP, WPa cycle

Claims (12)

A method performed by a sensor controller configured to control a sensor configured to detect the stylus.
A step of continuously transmitting a plurality of first control signals through the sensor over a continuous transmission period longer than the execution cycle of the stylus for receiving the uplink signal from the sensor.
After the continuous transmission period, a step of receiving the downlink signal from the stylus over a predetermined reception period, and
A step of determining whether or not the stylus is detected according to the detection result of the downlink signal within the predetermined reception period, and
How to include. The sensor controller is
It is determined that the stylus has been detected in response to the detection of the downlink signal within the predetermined reception period.
In response to the fact that the downlink signal is not detected within the predetermined reception period, the continuous transmission of the plurality of first control signals is performed again after a predetermined time.
The method according to claim 1. After determining that the stylus has been detected, the sensor controller transmits a second control signal having a time length shorter than the continuous transmission period via the sensor.
The method according to claim 1. The sensor controller transmits a second control signal via the sensor after the continuous transmission period and before the predetermined reception period.
The method according to claim 1. The sensor controller performs the downlink signal reception operation after the continuous transmission period, and when the downlink signal is received by the reception operation, the second sensor controller indicates a command to the stylus via the sensor. Send control signals,
The method according to claim 1. The uplink signal reception operation is continued until the end of the continuous transmission period when the first control signal is received by the reception operation.
The method according to claim 1. The stylus transmits the downlink signal after detecting the end of the continuous transmission period.
The method according to claim 6. With a stylus
Includes a sensor controller configured to control a sensor configured to detect the stylus.
The sensor controller is
A plurality of first control signals are continuously transmitted through the sensor over a continuous transmission period longer than the execution cycle of the stylus for receiving the uplink signal from the sensor.
After the continuous transmission period, the downlink signal reception operation from the stylus is performed for a predetermined reception period.
It is determined whether or not the stylus is detected according to the detection result of the downlink signal within the predetermined reception period.
system. The sensor controller is
It is determined that the stylus has been detected in response to the detection of the downlink signal within the predetermined reception period.
In response to the fact that the downlink signal is not detected within the predetermined reception period, the continuous transmission of the plurality of first control signals is performed again after a predetermined time.
The system according to claim 8. A stylus configured to communicate with a sensor controlled by a sensor controller.
With a receiving circuit that executes the operation of receiving the uplink signal from the sensor in a period shorter than the continuous transmission period, which is the period in which the sensor controller continuously transmits a plurality of first control signals via the sensor. ,
In response to the reception circuit receiving the first control signal within the continuous transmission period, the sensor receives the first control signal for a predetermined reception period set after the continuous transmission period, and the stylus detects the signal. A transmission circuit that transmits a downlink signal processed by the sensor controller to the sensor to determine whether or not it has been performed.
Stylus including. The uplink signal reception operation is continued until the end of the continuous transmission period when the first control signal is received by the reception operation.
The stylus according to claim 10. The transmission circuit transmits the downlink signal after the end of the continuous transmission period is detected.
The stylus according to claim 11.

Images